During the current year we plan to continue our studies of how various hormonal and physical factors affect the degree of electrical coupling in smooth muscle cells of the gastrointestinal tract and uterus. We plan to study effects of estrogen and progesterone treatment, pregnancy and parturition. In addition, we will examine the effects of passive stretch on propagation parameters and tissue impedance. The degree of electrical coupling will be determined by means of tissue impedance measurements and analysis. We also plan to study the relationship between intestinal slow wave frequency and propagation velocity by electrically driving slow waves in vitro. These physiological studies will be accompanied by appropriate electron microscopic studies.